This invention relates to magnetic-tape recorders.
A magnetic-tape recorder typically includes a tape transport for moving a magnetic tape past record and replay heads, plus associated circuitry for energising the record head(s) in accordance with a signal or signals to be recorded and for amplifying and processing signals derived by the replay head(s) when the tape is replayed.
The tape transport itself generally comprises: spindles to carry the tape supply and take-up spools; a capstan (sometimes associated with a pinch roller) to engage the tape and move it at a constant speed past the heads; rollers with fixed axes to guide the tape in the desired path from the supply spool via the capstan and heads to the take-up spool; rollers with movable axes to engage the tape and guide and maintain it in tension along the tape path; and motors (for example, servo-motors) to rotate the spindles and capstan at the required speed.
One of the problems encountered with prior art tape recorders is flutter: relatively rapid fluctuations of low amplitude in the speed of movement of the tape past the heads. Flutter causes distortion as between the input signal during recording and the output signal produced upon replay, particularly if the mode of recording involves frequency-modulation of a carrier signal which is recorded on the tape. It is an object of this invention to reduce flutter in magnetic-tape recorders.